Apparatus for producing mineral wool



Oct. 19, 1948. I I H. c. SMITH 2,451,582

'7 APPARATUS FOR PRODUCING MINERAL WOOL Filed Sept. 9, 1941 2 sheets sheet 1 .Zvvmfar film/'21. Will.

Oct. 19, v1948. H. 0. SMITH APPARATUS FOR PRODUCING MINERAL WOOL I 2 Sheets-Sheet 2 med Sept. 9, 1941 Patented Oct. 19,1948

i UNITED sT 'r s PATENT OFFICE APPARATUS FOR PRODUCING MINERAL WOOL Herbert (J. Smith, LosAngeiea CaiiL, assignor, by direct and mesne assignments, to American Rock Wool Corp.,.Wabash, Ind., a corporation of Indiana Application September a. 1941, Serial No. 410,177

' 3 Claims.

This invention relates to method and apparatus for producing mineral wool, commonly 1 known as rock wool. I aim to provide a mineral started and stopped with maximum ease; and

which is capableof producing a continuous stream of slag at uniform rate and temperature.

In another of its aspects, my invention contemplates a novel method ofproducing mineral wool, and particularly of feeding raw materials into a slag furnace.

Other major advantages are inherent in my invention and how those, as wella s those specifically set forth hereinabove, are accomplished will become apparent from the following detailed description of presently preferred examples thereof, for which purpose I shall refer to the accompanying drawings, in which:

Fig. 1 is a view partly in elevation and partly in longitudinal section;

Fig. 2 is a cr'oss-section on line 2--2 of Fig. 1; Fig. 3 is a view partly in elevation and partly in vertical section showing a variational form;

Fig. 4 is a section on line 4-4 of Fig. 3; and Fig. 5 is a longitudinal sectional view of a further variational form.

Referring now to Figs. l and 2 of the drawings; I show generally a furnace F, a fuel injecting unit T, a raw material feeder H and a steam jet S.

The furnace F is of the reverberatory type supported on a base B and is shown as comprising a metal casing 5 having an inner lining 6 of a, suitable refractory material such, for instance, as fire brick, fire clay,. ganister, carborundum fire sand or chromite block. The forward end ill of the furnace-that is, the end through which the fuel and raw material are introducedis capped by a similarly lined end wall 8, having an opening 9 and said forward end is substantially horizontally disposed. The adjoining melting zone portion H is disposed upwardly at an angle and communicates with a stack I2. The hearth I5 has a tap hole I! at the junction between end l0 and the melting zone H. The fuel injection unit comprises a mixing tube 20 projecting into opening 9 and a fuel jet 2i by which fuel under pressure is injected into the venturi 20a of the mixing tube 20, air being drawn in at the opening 22.

' For feeding the raw material M to the furnace, I provide a hopper 25 which has a discharge spout 21 discharging material into tube 20 through air inlet 22. Aconveyor screw 30 is rotatably mounted in the hopper on brackets II, 32 carried by the hopper and is driven by a wheel 33, the wheel .belng driven by a belt 34 leading from a power element, not shown. The raw materials are placed in the hopper in a flnely ground state and as-they are discharged into the mixing tube 20 they are picked up and propelled well up into the furnace along with the combustion mixture. Thus when the materials reach the furnace they are in intimately admixed and blended state.

zone II it becomes molten slag and slowly gravitates towards the tap hole H, a continuous stream of slag 40 pouring out of the tap hole I1 in the path of the steam discharged from jet 5, which acts to blast the molten slag into the mineral wool product in the well known manner. Other suitable types of feeders may be substituted for feeder H.

From the foregoing it will be-observed that the rate of production may be easily controlled by regulating the rate of introduction of the raw material, and since the slag, after being melted, travels continuously towards the heat source it leaves the furnace at "maximum and uniform fluidity, which results in a high and uniform grade ofmineral wool.

When beginning operations, it is desirable to thoroughly heat the furnace before beginning the feeding of raw materials and when stopping operation, it is desirable to stop the feed of material somewhat before the fuel is stopped in order to clear the. furnace.

While my device is particularly adapted for the use of'gas or oil fuels, it will be readily apparent to those skilled in this art that other fuels,

' such as powdered coke, may be fed under pressure to the furnace instead of gas or oil and thus the fuel'injecting unit T may be considered as intended for any suitable type of fuel.

In Figs. 3 and 4, I show a variational form of unit employing my invention. There I show a reverberatory furnace F comprising a casing 50 lined with fire brick 5| or other suitable refractory. The combustion chamber 53 is circular in cross-section andthe lower portion 54 is conical, having a tap hole 55. The cover 51 is arched and a stack 58 communicates with the furnace through a hole 58a. A tubular baiile 59 depends into the combustion chamber 53 to prevent raw material injected into the fur" ace from passing When the raw material is thus propelled far up into the melting out through the stack. In this form of'device the fuel and raw material are injected into the furnace by burners T, T and 1' and feeders H, which are constructed as before described, in a direction tangentially .of the combustion chamber. There are three injection points provided by circumferentially spaced holes 60, 60a. and 60b through the sidewall of the furnace, said holes being disposed preferably in different horizontal planes. In operation, the raw material enters the furnace tangentially in the fuel stream and, as is the case in operation of the device of Figs.1 and 2, being subjected directly to the flame as well as heat from the walls, rapidly melts and gravitates along the side walls to the tap hole 55 where it passes out 'into the path of the steam blast from Jet J which converts the molten slag into mineral wool. The furnace is supported on a suitable base B.

In some cases it may be desirable, instead of utilizing tap hole 55, to maintain a lake of molten slag in the lower portion 54 of the furnace. In such event, instead of placing the tap hole at the bottom, a tap hole as shown by dotted line 55a may be provided through the side wall at the desired slag level denoted by dotted line 80. In that case the steam jet J would be positioned to discharge into the slag stream which would pour from hole 55a.

In Fig. 5, I show another form which my invention may take. Here I show a furnace comprising a casing 5' lined with a suitable refractory such as fire brick 6' and having a hearth l5 sloping towards the rear end 10 of the furnace. A stack II is provided through the arched top wall 12 and communicates with the furnace between spaced transverse baffles 14. Front end 15 has an opening to receive the fuel mixing tube through which fuel from jet 2| and raw material from feeder H" enter the furnace in the manner before described. An auxiliary fuel injecting unit T" discharges combustion mixture into the furnace through opening '16 in a direction diagonally downwardly onto the outfiowing slag stream 40'. Preferably, no raw material, is fed through the auxiliary fuel injecting unit to insure that no unmelted particles or beads will pass out in the sla stream. Steam jet J" plays on the outpouring slag to blast it into mineral wool. In this form of device I make provision for maintaining a lake of molten slag in the furnace by plugging the bottom tap hole 11 and using the upper tap hole 110., in which event a lake of slag, as defined by dotted line 80, would be maintained in the furnace with the auxiliary fuel injecting unit playin directly upon it to maintain the lake of slag in a state of high fluidity. Baffies I4 prevent light, unmelted particles of raw material from escaping through the stack. A suitable base B" supports the furnace.

While I have resorted to considerable detail for the purpose of making my invention understood, I wish it understood that within the broader scope of my invention, as defined by the appended a combined stream of fuel and pulverulent raw material into the front end of the furnace in a direction so angularly disposed with relation to the plane of the hearth as to be directed angularly into the flowing stream of molten material, said discharge opening communicating with the chamber in a plane with the inner surface of the hearth whereby to prevent formation of a pool of molten material on the hearth.

2. A furnace for continuously converting raw material into molten material, comprising refractory walls defining an elongated combustion chamber havinga hearth disposed in a declining plane from one end towards the other, a stack communicating with the chamber, means for supplying raw material to the chamber, a discharge outlet in the lower end of the hearth, said discharge opening communicating with the chamber in a plane with the inner surface of the hearth whereby to prevent formation of a pool of molten material on the hearth,'and means for directing a heating flame into the chamber anguiarly against the hearth adjacent said discharge outlet.

3. In a furnace of the class described, stationary refractory walls defining an elongated combustion chamber having a, hearth inclining from adjacent its front end towards its rear end, a stack communicating with the chamber, nozzle means for directing a heating flame and pulverulent raw material into the chamber from the front end thereof, and a discharge opening through the hearth adjacent the front end thereof, said dis- REFERENCES crrEp The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 241,108 Wiesebrock May 3, 1881 729,009 Sutton May 26, 1903 1,073,462 Banes Sept. 16, 1913 1,160,621 Klepinger (b) Nov. 16, 1915 1,164,653 Klepinger (a) Dec. 21,1915 1,206,771 Barr Nov. 28, 1916 1,490,012 K-apteyn Apr. 8, 1924 1,500,651 Smith July 8, 1924 1,656,828 Powell Jan. 17, 1928 1,863,708 Zotos June 21, 1932 1,893,913 Saint Jacques Jan. 10, 1933 1,904,781 Crawford Apr. 18, 1933 1,929,308 Clark Oct. 3, 1933 1,932,355 Scheidt Oct. 24, 1933 1,953,034 Willetts Mar. 27. 193 1,964,915 Haswell et al July 3, 1934 2,057,393 Powell Oct. 13, 1936 2,126,411 Powell Aug. 9, 1938 2,131,599 Shrum Sept. 27, 1938 2,242,089 Ramseyer May 13, 1941 2,249,410 Wilson July 15, 1941 2,358,903 Zotos Sept. 26, 1944 FOREIGN PATENTS Number Country Date 552,123 Germany May 5, 1931 356,611 Great Britain Sept. 10, 1931 780,140 France Jan. 24, 1935 

